[Enhancement] Allow admin to merge pr with protected file changes (#12078)

* [Enhancement] Allow admin to merge pr with protected file changes

As tilte, show protected message in diff page and merge box.

Signed-off-by: a1012112796 <1012112796@qq.com>

* remove unused ver

* Update options/locale/locale_en-US.ini

Co-authored-by: Cirno the Strongest <1447794+CirnoT@users.noreply.github.com>

* Add TrN

* Apply suggestions from code review

* fix lint

* Update options/locale/locale_en-US.ini

Co-authored-by: zeripath <art27@cantab.net>

* Apply suggestions from code review

* move pr proteced files check to TestPatch
* Call TestPatch when protected branches settings changed

* Apply review suggestion @CirnoT

* move to service @lunny

* slightly restructure routers/private/hook.go

Adds a lot of comments and simplifies the logic

Signed-off-by: Andrew Thornton <art27@cantab.net>

* placate lint

Signed-off-by: Andrew Thornton <art27@cantab.net>

* skip duplicate protected files check

* fix check logic

* slight refactor of TestPatch

Signed-off-by: Andrew Thornton <art27@cantab.net>

* When checking for protected files changes in TestPatch use the temporary repository

Signed-off-by: Andrew Thornton <art27@cantab.net>

* fix introduced issue with hook

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Remove the check on PR index being greater than 0 as it unnecessary

Signed-off-by: Andrew Thornton <art27@cantab.net>

Co-authored-by: techknowlogick <matti@mdranta.net>
Co-authored-by: Cirno the Strongest <1447794+CirnoT@users.noreply.github.com>
Co-authored-by: zeripath <art27@cantab.net>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>

models/pull.go

@@ -45,6 +45,8 @@ type PullRequest struct {
 	CommitsAhead    int
 	CommitsBehind   int
 
+	ChangedProtectedFiles []string `xorm:"TEXT JSON"`
+
 	IssueID int64  `xorm:"INDEX"`
 	Issue   *Issue `xorm:"-"`
 	Index   int64